Railway signaling apparatus



Dec. 5, 1939. w. P. PLACE RAILWAY SIGNALING APPARATUS Filed April 6,1939 W 1g X I [b 14 i;

W' ml Com al Circuit.

INVENTOR we! 121 66209.

HIS ATTOR N EY Patented Dec. 5, 1939 v UNITED STATES PATENT OFFICERAILWAY SIGNALING APPARATUS Willard P. Place, Wilkinsburg, Pa., assignorto The Union Switch & Signal Company, Swissvale, Pa., a corporation ofPennsylvania Application April 6, 1939, Serial No. 266,368

11 Claims. (Cl. 2l634) My invention relates to railway signalingappreferably consists of several cells connected in paratus, and moreparticularly to apparatus for series to produce a relatively highvoltage, such railway track circuits. as, for example, a ten voltstorage battery.

A feature of my invention is the provision of The transmitting relay orcoder CT :is prefer- 5; novelv and improved apparatus for supplying aably of the neutral relay type having slow pick- 5".

track circuit with periodically interrupted or time up characteristics.In the form here shown the spaced current impulses of relatively highvolttransmitting relay CT is provided with a top or age and shortduration, and the duration of which operating winding i and a lower orretarding is varied according to dry and wet ballast condi- Winding 5,the winding 5 being short circuited tions so that a substantiallyuniform energizaover a back contact 6 of the relay so that the relay 10tion of the track relay is efiected over a relatively is slow to pick upwhen the operating winding 4 is wide range of ballast resistance. Thehigh voltenergized. The auxiliary relay AR is preferably age of thecurrent impulses is of aid to the shunta quick acting neutral relay.

ing sensitivity of the track circuit because such The track battery 3 isconnected across the Ill, voltage breaks down the rail film resistance.rails la and lb over the two conductors 6 and 1 V The short duration ofsuch current impulses reand preferably in a manner so as to supply thequires only a low energy output of the track track circuit with currentof a predetermined battery or other current source. Another featurepolarity. To be explicit, the negative terminal of my invention is theprovision of novel and imof battery 3 is connected with conductor l overproved track relay means for a track circuit which a protective deviceor fuse 8 and a front contact 20 is responsive to time spaced currentimpulses 9 of the transmitting relay CT, and the positivenotwithstanding such impulses are badly disterminal of battery 3 s c edW t c ufitorted in wave form and which means also makes tor 6 over acurrent limiting resistor It. The it possible to maintain a signalcontrol relay eneroperating winding 4 of relay CT is connected 5 gizedfrom a low voltage source of control curacross battery 3 over the backcontact ll of the 5 rent. Other features and advantages of myinauxiliary relay AR as will be readily understood vention will appearas the specification progresses. by an inspection of Fig. l. The windingii of I shall describe two forms of apparatus embodythe auxiliary relayAR is connected across the ing my invention, and shall then point outthe track rails by being connected directly with the novel featuresthereof in claims. conductors 6 and l which conductors possess an 30 Inthe accompanying drawings, Figs. 1 and 2 appreciable amount of ohmicresistance. It folare diagrammatic views of two different forms of lowsthat when the front contact 9 of relay CT apparatus each of whichembodies my invention. is closed and current is supplied from trackbat-' In each of the two views like reference charactery 3 to the trackcircuit over conductors 6 and ters designate similar parts. l thewinding ll of relay AR receives current in 35.

Referring to Fig. 1, the reference characters la shunt with the trackcircuit. With relay AR and lb designate the track rails of a stretch ofenergized and picked up opening back contact ll railway over whichtrafiic normally moves in the the current to the operating winding 4 ofrelay direction indicated by an arrow and which'rails CT is interruptedand relay CT is deenergized 40 are formed by the usual insulated railjoints with and immediately releases opening front contact 40 a tracksection WX. The track section W--X 9 and removing current from the trackcircuit is provided with a track circuit for signaling. and also fromthe winding I? of relay AR. Relay This track circuit for section W-Xcomprises AR is now deenergized and releases closing back transmittingor coding means for supplying across contact H to reenergize theoperating winding 4 the rails la and lb at the exit end of the sectionof the transmitting relay CT. It is apparent that 45 periodicallyinterrupted or time spaced current relays CT and AR will have a cyclicoperation, impulses, and a track relay connected across the the cycleinterval being determined largely by rails at the entrance end of thesection. The the slow pick-up period provided for the relay means forsupplying time spaced current impulses CT and relay CT being retainedpicked up a relamay take different forms and as here shown it tivelyshort period of each cycle interval because 50 includes a track battery3, a transmitting relay of the relatively quick pick-up period of relayAR. or coder CT, an auxiliary relay AR, a ,current It is to be notedthat the ballast resistance limiting resistor ill, a protective device 8and two path between the track rails la and lb forms a track conductors6 and 1 connected to the rails shunt path to the winding l2 of relay AR.Hence la and lb, respectively. The track battery 3 under dry ballastconditions and the rail to. rail 55 ballast path of relatively highresistance so that the leakage current is low, the voltage drop atresistor H3 is low and substantially the full voltage of battery 3 isapplied to winding I2 of relay AR and relay AR picks up correspondinglyquick. Under wet ballast conditions and the rail to rail resistance pathof relatively low resistance the increased flow of leakage currentcauses a relatively large voltage drop at resistor Hi and the voltageapplied to the operating winding l2 of relay AR is correspondingly low,causing that relay to pick up correspondingly slow. Consequently, underdry ballast conditions the period the transmitting relay CT remainspicked up is correspondingly short due to relay AR picking up quicklysothat the duration of the current im.-, pulse supplied to the trackcircuit over front contact 9 of transmitting relay CT is correspondinglyshort. Under wet ballast conditions the period the transmitting relay CTremains picked up is correspondingly long due to relay AR picking upslowly so that the duration of the current impulse supplied to the trackcircuits is c0rresnondingly long.

It is to be seen, therefore, that time spaced impulses of direct currentof a predetermined polarity are supplied to the track circuit of sectionWX, the impulses being of relatively high voltage and of short duration,the duration of the impulses being short compared with the intervalbetween successive impulses and the duration of the impulses beingautomatically varied according to the ballast conditions.

It should be observed that Contact a of the transmitting relay CT ispreferably of the socalled safety type, that is, a contact adaptable ofbreaking a high voltage. It should also be observed that in the event ofa circuit cross or ground and the transmitting relay CT fails in itsoperation with front contact 9 closed so that the magnitude of thecurrent supplied from battery 3 is large, the fuse 3 would shortly meltand open this circuit removing all current from the track rails.

The track relay for the track circuit of section WX is a direct currentrelay TRI, the operating winding ll of which is connected across therails la and lb over conductors 13 and [4, respectively. A resistor land a rectifier iii are connected in multiple across the operatingwinding 4i of relay TRI to give the relay quick pickup and slow releasecharacteristics.

.When the section WX is unoccupied, the short high Voltage currentimpulses applied across the railseffectively energize and pick upthetrack relay TRl, the relay TR! remaining picked up from one impulse tothe next due to its slow release characteristic. The total energyavailable for energizing the relay TRI is substantially uniform underboth dry and wet ballast conditions since under dry ballast conditionsthe voltage of the impulses will be correspondingly high and theduration of each impulse will be correspondingly short, and under Wetballast conditions the voltage of the impulses will be correspondinglylow and the duration of the impulses will be correspondingly longbecause of the action of the auxiliary relay AR as explainedhereinbefore. I

It is to be noted that since the track relay TRl is slow releasing incharacter and is energized and retained picked up from one currentimpulse to the next the wave form of the individual impulses may bebadly distorted because of track circuit conditions without causing anunfavorable operation of relay TRI.

When the track section WX is occupied relaysAR and CT are periodicallyoperated, such operation being aided by the resistance possessed byconductors l3 and l, and the relatively high voltage of the currentimpulses breaks down the rail film resistance and track relay TR! isshunted, the track circuit for section WX having a relatively highshunting sensitivity.

The track relay TB! is used to control any desired signal controlcircuit of the usual form and as here shown the signal control circuitincludes front contact ll of relay 'IRl. I

In Fig. 2, the track rails la and lb of a stretch of railway are formedwith a track section WX having a track circuit the same as in Fig. 1.The means for supplying time spaced current impulses of relatively highvoltage and short duration to the track circuit of section WX of Fig. 2is the same as in Fig. 1.

. In Fig. 2, the track relay means includes a code following relay TRZconnected across the rails at the entrance end of the section WX. Hence,when section WX is unoccupied the track relay TR2 is effectivelyenergized and picked up closing front contact 22 during the on period ofeach current impulse supplied to the track circuit of section WX, andrelay TRB is deenergized and released during the off period of eachcurrent impulse, that is, during the interval between successiveimpulses. Since the duration of the current impulses is short comparedWith the duration between successive impulses the on period of the relayTRZ is short compared with the off period of the relay. The energyavailable, however, for picking up the track relay TRZ in response toeach current impulse is substantially uniform over a relatively widerange of ballast resistance due to the operation of the auxiliary relayAR causing the individual impulses to be correspondingly short under dryballast conditions and correspondingly long under wet ballastconditions. Such unequal and varied on and off periods in the operationof relay TR2 isimmaterial to the operation of the apparatus governed bythe relay TR? as will shortly appear. When the track section WX isoccupied the track relayyTRZ is shunted and is inactive, the trackcircuit for section WX having a relatively high degree of shuntingsensitivity due to the relatively high voltage of the current impulses.

The track relay means of Fig. 2 also includes a polar relay PR, adecoding transformer DT, a control relay CR and a low voltage controlbattery H3.

The polar relay PR is provided with a normal winding NW and a reversewinding RW, the arrangement being suchthat when normal winding NW is.energized over a circuit to be shortly described the polar contactmembers I9, 20 and 2! of relay PR are operated to the normal orleft-hand position as viewed in Fig. 2. When the reverse winding RW isenergized by a circuit tions, and notwithstanding the wave form of theof the relay from its last position, the polar armature moves to itsother extreme position although the energizing current ceases.

A relay which may be made to operate in a manner just described isdisclosed in the Letters Patent of the United States No. 1,790,671,granted February 3, 1931, to Branko Lazich for Electrical relays. In theinstant application the polar relay PR is provided with two windingsdisposed for. reversibly energizing the relay whereas in the patent therelay is shown provided with a single winding to which current isreversibly supplied, such equivalent arrangements of the windings of apolar relay being readily understood by those skilled in the art.

When relay TRZ is picked up closing front contact 22 current flows frombattery 18 over front contact 22 of relay TRTZ, reverse winding RW ofrelay PR, normal polar contact Iii-23 and back to battery 58, and relayPR is operated to move its contact members I9, 20 and 2| to the reverseor right-hand position. On the next current impulse of the track circuitand track relay TRZ is again picked up closing front contact 22, currentflows from battery [3 over front contact 22, normal winding NW of relayPR, reverse polar contact ill-24 of relay PR and back to battery 18, andrelay PR. operates its contact members i9, 29 and 2! to the normal orleft-hand position. It follows that the polar relay PR is operated toits reverse position in response to each odd impulse of the trackcircuit current and is operated to the normal position in response toeach even impulse of the track circuit current. Furthermore, because ofthe operating characteristics of relay PR it is clear that the relaywill be operated notwithstanding the on and off periods of the operationof the code following relay 'IRZ are unequal and are varied.

With polar relay PR thus operated current from battery i8 is alternatelysupplied over normal polar contact 20-26 and reverse polar contact 2ll2lto the two portions of the primary winding 25 of transformer DT. Suchalternate energization of the two portions of primary winding 25 inducesan alternating electromotive force in the two portions of the secondarywinding 28 of transformer DT and which electromotive force is rectifiedand applied to the winding 29 of control relay CR. over normal polarcontact 2I-3ii and reverse polar contact 2|3l with the result thatrectified current flows in the winding 29 always in the same directionand relay CR is effectively energized and picked up closing frontcontact 32 interposed in a signal control circuit. Relay CR- remainspicked up closing front contact 32 as long as relay PR is operated sincerelayCR is provided with slow release characteristies. The ratio of theturns of the primary winding 25 to the turns of the secondary winding 23of transformer DT is chosen so that relay CR is effectively energizedfrom battery 18 when battery I8 is a single cell low voltage battery.The condensers 33 and 34 may be provided and connected as shown in Fig.2 to suppress sparking at the contacts of the polar relay PR.

It is to be seen, therefore, that the signal control circuit includingfront contact 32 of relay CR is effectively governed from a low voltagecontrol battery and in response to track circuit current impulses whichare of relatively short duration compared with the duration betweensuccessive impulses, and which durations are varied in response tochanges in ballast condicurrent impulses may be badly distorted.

It should be observed that the windings NW and RW may be connecteddirectly with the track rails of section W--X andthe polar relay PRoperated directly by the track circuit current impulses.

Although in both Figs. 1 and 2 the source of supply for the trackcircuit is shown as a battery 3 of the voltage of the order of 10 volts,it is to be understood that my invention is not limited to a battery ofsuch voltage and connected with the polarity as shown in the drawing.Also an alternating current source maybe used onthe track circuit andrelays CT and AR made alternating current relays of any of'the severalwellknown types. Although I have herein shown and described only twoforms of apparatus embodying my invention, it is understood that variouschanges and modifications maybe made therein within the scope of theappended claims without departing from the spirit and scope of myinvention.

Having thus described my invention, what I claim is:

1. In combination, a track section, a source of direct current,transmitting means operative to connect said source across the rails atone end of the section for supplying to said rails time spaced impulsesof current, means connected across the rails at said one end of thesection variably afiected by wet and dry ballast conditions of thesection to control the duration of each of said impulses of current, anda track relay connected across the rails at the other end of the sectioneffectively energized by said impulses of current.

2. In combination, a track section, a source of direct current,transmitting means for periodically connecting said source across therails at one end of said section to supply recurrent impulses of directcurrent to said rails, means connected with the rails responsive tochanges in ballast conditions of said section to vary the duration ofeach of such current impulses to cause such impulses to be relativelyshort under dry ballast conditions and relatively long under wet ballastconditions, and a track relay connected across therails at the other endof said section energized by said current impulses at substantially thesame energy level for both dry and Wet ballast conditions.

3. In combination, a track section, a source of direct current, atransmitting relay effective when energized to supply current from saidsource to the rails at one end of said section, an auxiliary relayconnected across the rails at said one end of the section energized bysaid current supplied to the rails for picking up said auxiliary relayin an interval which is varied due to variations in the shunting actionof dry and wet ballast conditions of the section, means including a backcontact of said auxiliary relay to energize said transmitting relay tocause the current supplied to the rails to be relatively short currentimpulses under dry ballast conditions and relatively long currentimpulses under wet ballast conditions, and a track relay connectedacross the rails at the other end of said section energized by saidcurrent impulses at an energy level,

4. In combination, a track section, two conductors connected one witheach rail at one end of the section; atrackbattery;aitransmitting-relay, means includinga front contact of said transmitting relay toconnect said battery with said conductors to-supply current to the railsof said section, an auxiliary relay having its winding connected withsaidconductors to pick up the auxiliary relay subsequent to the closingof said front contact of the transmitting relay in a time intervalvaried by the variations in the shunting action caused by dry and wetballast resistances of the section, means including a back contact ofsaid auxiliary relayto connect 'a-winding of said transmitting relayacross said battery to cause a cyclic operation of said relays with theperiod the transmitting relay is picked up and current supplied to the.rails correspondingly short under dry ballast resistance andcorrespondingly long under wet ballast resistance, and a track relayconnected across the rails at the other end of the section energized bycurrent thusintermittently supplied to the rails at an energy levelsubstantially the same for both dry and wet ballast resistances.

5. In combination, a track section, two conductors connected one witheach rail at the exit end of said section, a track battery of relativelyhigh voltage, a slow pick-up relay, an auxiliary relay, means includinga front contact of said slow pick up relay to connect said battery withsaid conductors to supply current to the rails of said section at arelatively high voltage, means to connect a winding of said auxiliaryrelay with said conductors for picking up the auxiliary relay subsequentto the closing of said front contact of the slow pick-up relay in a timeinterval dependent upon the shunting action of the ballast resistance ofthe section, means including a back contact of said auxiliary relaytoconnect a winding of said slow pick-up relay, across said battery toprovide a cyclic operation of said relays with the period the frontcontact of the slow pick-up relay is closed correspondingly short underdry ballast conditions and correspondingly long under wet ballastconditions, and a track relay ccnnected across the rails at the entranceend of the section energized by the current impulses supplied to therails when the section is unoccupied at substantially the same energyleVeHrrespective of ballast conditions and said track relay effectivelyshunted when the section is occupied due to the high voltage of suchcurrent impulse breaking down the rail film resistance.

6. In combination, a track section, two con ductors connected one witheach .rail at the exit end of said section, a track battery of the order1 of ten volts, a transmitting relay, an auxiliary relay, meansincluding a front contact of said transmitting relay to connect saidbattery with said conductors to supply current to the rails of saidsection, means to connect a winding of said auxiliary relay with saidconductors to pick up the auxiliary relay when said front contact of thetransmitting relay is closed in a time interval varied due to the variedshunting action of the ballast resistance of the section, meansincluding a back contact of said auxiliary relay to connect a Winding ofsaid transmitting relay across said battery to cause a cyclic operationof said relays with the period the transmitting relay is picked up eachcycle and current supplied to the rails relatively short under dryballast conditions and relatively long under wet ballast conditions, and

- a track relay connected across the rails at the entrance end of thesection energized by said current impulses when the section isunoccupied at substantially the same energy level for both dry and wetballast conditions and said relay shunted when the section is occupiedwith high sensitivity due to the ten volts of such current impulsesbreaking down the rail filmresistance.

'7. In combination, a track section, a track battery of theorder of tenvolts, a slow pick-up relay, a quick acting auxiliary relay, means including a back contact of said auxiliary relay to connect a winding ofsaid slow pick-up relay across said battery to energize said slowpick-up relay, means including a front contact of said slow pick-uprelay to connect a winding of said auxiliary relay across said batteryto energize said auxiliary relay and cause a cyclic operation otsaidrelays, other means including said front contact of the slow-pickeuprelay to connect said battery across the rails at one end of the sectionto supply to the rails of said section recurrent impulses of directcurrent eachoi which has a peak voltage of the order of ten volts and ashort duration due to the quick pick-up interval of said auxiliaryrelay, and a track relay connected across the rails at the other end ofthe section eiiectively energized by such current impulses when thesection is unoccupied and efifectively shunted when the section isoccupied due to said peak voltage of said impulses breaking down therail film resistance.

8. In combination, a track section, transmitting means including asource of direct current and a vibratory contact connected across. therails at one end of said section for supplying to the rails time spacedimpulses of direct current, a polar relay having a normal and a reverseenergizing windin and characterized by polar contact members which'whenmoved away from one extreme position move to the other extreme positionalthough the energizing current ceases, a first circuit including thereverse winding and a normal polar contact of said polar relay madeefiective to operate the polar relay in response to each odd numberedrail current impulse, a second circuit including the normal winding anda reverse polar contact of said polar relay made efiective to operatethe polar relay in response to each even numbered rail current impulse,whereby said polar relay is operated in step with said time spacedcurrent impulse supplied to the rails, and a signal control circuitcontrolled by, such operation of said polar relay.

9. In combination, a track section, transmitting means including aperiodically operated contact and a source of direct current connectedacross the rails at one end of the section to supply to the rails timespaced impulses of direct current, a track relay connected across therails at the other end of the section biased to one position andoperated to a second position in response to each of said currentimpulses, another source of direct current, a polar relay having anormal and a-revers'e winding and characterized by polar contact memberswhich when moved away from one extreme position move to the otherextreme position although the energizing current ceases; a first circuitincluding said other source, asecond position contact of said trackrelay, said reverse winding and a normal polar contactof said polarrelay; a second circuit including said other source, a second positioncontact of said track relay, said normal winding and a reverse polarcontact of the polar relay; a transformer, a signal control relay; meansincluding said other source and a normal and a reverse polar contact ofsaid polar relay for alternately supplying current to two portions ofthe primary winding of said transformer, other means including a normaland a reverse polar contact of said polar relay to alternately connecttwo portions of the secondary winding of said transformer to saidcontrol relay to energize said control relay by current induced in saidsecondary winding, and a signal control circuit governed by said controlrelay.

10. In combination, a track section, transmitting means including asource of direct current and an operated contact connected across therails at one end of said section to supply to the rails time spacedimpulses of direct current, a track relay connected across the rails atthe other end of said section biased to one position and operated to asecond position in response to each of said current impudses, a polarrelay having a normal and a reverse Winding, another source of directcurrent; a first circuit including said other source, a second positioncontact of said track relay, said reverse winding and a normal polarcontact of the polar relay; 2. second circuit including said othersource, a second position contact of said track relay, said normalwinding of the polar relay and a reverse polar contact of the polarrelay; and a signal control circuit controlled by said polar relay.

11. In combination, a track section, a track battery of the order of tenvolts, a slow pick-up relay, a quick acting relay, means including aback contact of said quick acting relay to connect a winding of saidslow pick-up relay across said battery, means including a front contactof said slow pick-up relay to connect a winding of said quick actingrelay across said battery to cause a cyclic operation of said relayswith said slow pick-up relay picked up for a relatively short period ofeach cycle interval, means including a front contact of said slowpick-up relay to connect said battery across the rails at one end of thesection to supply to the rails time spaced impulses of direct current ofrelatively short duration and of a voltage of the order of ten volts,and a track relay connected across the rails at the other end of thesection eiTectively energized when said section is unoccupied by saidcurrent impulses with a small expenditure of energy by said battery andsaid track relay highly sensitive to the train shunt when the section isoccupied due to the breaking down of the rail film by said voltage ofthe impulses.

WILLARD P. PLACE.

